A semiconductor substrate of Group III-V compound such as GaAs or GaP covered uniformly with powder of the same kind of semiconductor with grain diameters of 20-500.mu. is placed in a quartz tube and a small piece of zinc is also placed in the tube at a place separated from the substrate, the zinc is heated above 700.degree. C to evaporate it by a heating coil placed around the zinc, the substrate is also heated by a coil around it independently of the zinc, and a zinc gas is flowed by being carried by an argon gas over the heated substrate to diffuse zinc into the substrate from the vapor phase through the cover.
A method of forming a highly stable oxide on gallium arsenide containing compound semiconductors. A native oxide is grown on the surface of the semiconductor and dried during a suitable baking cycle. The oxide is then annealed at a temperature which is significantly higher than that of the baking cycle. This annealing step densifies the oxide and renders it particularly stable and impervious to impurities. In a particular embodiment, a diffusion mask is formed in accordance with the invention to permit selective area diffusion of impurities into a gallium arsenide containing compound semiconductor.
The invention relates to a method of diffusing a doping material in a semiconductor body via the vapour phase. Two doping sources are used which differ in composition but have the same doping material. The diffusion operation consists of successive phases in which always one of the doping sources is used.
Method of diffusing vapor impurity into semiconductor body comprising providing impurity source and semiconductor body in separate open-ended vessels, inserting vessels in furnace and heating semiconductor body to diffusion temperature range before initiating diffusion on significant scale, and diffusing impurity into semiconductor body. Also, product made by method.
Semiconductor monocrystals composed of Group III-V compounds such as GaAs having a p-conductive layer therein are produced by masking a surface of a Group III-V monocrystal with a protective layer composed of a material, such as silicon dioxide which allows Group III elements to diffuse through the layer while preventing diffusion of Group V elements, subjecting the masked monocrystal to a heat treatment in a gaseous atmosphere so as to remove some of the Group III atoms from the monocrystal and then doping the treated monocrystal with an element of Group II, such as Zn.
The electrical carrier concentration of Group I-III-VI compound semiconductors containing copper as the Group I element is controlled by a heat treatment in an atmosphere containing an overpressure of one or two of the constituent elements. The p-type conductivity of these semiconductors can, by this method, be controllably varied over several decades of carrier concentration and some exemplary materials have been made usefully n-type. All compounds of the class contemplated have been found to be direct band gap semiconductors and are capable of exhibiting coherent stimulated emission when optically pumped. Using these compounds and techniques, both homojunction and heterojunction lasers are contemplated from the infrared region of the spectrum, through the visible and into the ultraviolet.
